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%I #11 Mar 31 2012 10:33:03
%S 0,0,0,0,1,4,25,136,772,4953,35340,288335,2632792,26726855,296550560
%N Number of connected triangle-free graphs on n nodes with edge chromatic number 4.
%Y Cf. A207408.
%K nonn,more
%O 1,6
%A _Michael Sollami_, Feb 17 2012